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‘L2′ Will be the James Webb Space Telescope’s Home in Space

When you ask an astronomer about the James Webb Space Telescope’s orbit, they’ll tell you something that sounds like it came from a science-fiction novel. The Webb won’t be orbiting the Earth –instead we will send it almost a million miles out into space to a place called “L2.”

Copyright NASA

L2 is short-hand for the second Lagrange Point, a wonderful accident of gravity and orbital mechanics, and the perfect place to park the Webb telescope in space. There are five so-called “Lagrange Points” – areas where gravity from the sun and Earth balance the orbital motion of a satellite. Putting a spacecraft at any of these points allows it to stay in a fixed position relative to the Earth and sun with a minimal amount of energy needed for course correction.

The term L2 may sound futuristic and mysterious, but the name actually honors a Mathematician born in 1736. The Lagrange points were named after the Italian-born mathematician and astronomer Joseph-Louis Lagrange, who made important contributions to classical and celestial mechanics. Lagrange studied the “three-body problem” (so-called because three bodies are orbiting each other) for the Earth, sun, and moon in 1764, and by 1772 he had [...]

A Little Telescope Goes a Long Way

Copyright NASA\Ernie Mastroianni

NASA astronomers have successfully demonstrated that a David of a telescope can tackle Goliath-size questions in the quest to study Earth-like planets around other stars. Their work, reported today in the journal Nature, provides a new tool for ground-based observatories, promising to accelerate by years the search for prebiotic, or life-related, molecules on planets orbiting stars beyond our solar system.

The scientists reported on a new technique used with a relatively small Earth-based telescope to identify an organic molecule in the atmosphere of a Jupiter-size planet nearly 63 light-years away. The measurement revealed details of the exoplanet’s atmospheric composition and conditions, an unprecedented achievement from an Earth-based observatory.

The surprising new finding comes from a venerable 30-year-old, 3-meter-diameter (10-foot) telescope that ranks 40th among ground-based telescopes – NASA’s Infrared Telescope Facility atop Mauna Kea, Hawaii.

The new technique promises to further speed the work of studying planet atmospheres by enabling studies from the ground that were previously possible only through a few very high-performance space telescopes. “Given favorable observing conditions, this work suggests we may be able to detect organic molecules in the atmospheres of terrestrial planets with existing instruments,” said lead author Mark Swain, an astronomer [...]

The Coolest of Orbs

Copyright NASA/JPL-Caltech

An international team of astronomers using several telescopes has discovered what appears to be the coolest star-like body known, a brown dwarf called SDSS1416+13B. The dim ball of gas is roughly 400 degrees Fahrenheit (200 degrees Celsius). NASA’s Spitzer Space Telescope helped nail down the temperature of the object by observing at a particular range of light called mid-infrared.

Too small to be stars, brown dwarfs have masses lower than stars but larger than gas-giant planets like Jupiter. Due to their low temperature, these objects are very faint in visible light, and are detected by their glow at infrared wavelengths. They were originally dubbed “brown dwarfs” long before any were actually discovered, to describe bodies that are cooler, fainter and redder than “red dwarf” stars, with the color brown representing the mix of red and black.

To read more, visit: http://www.herts.ac.uk/news-and-events/home.cfm.

Theft of a million stars

theft-of-a-million-stars

Copyright ESA

Using ESO’s Very Large Telescope, a team of Italian astronomers reveal the troubled past of the stellar cluster Messier 12 – our Milky Way galaxy ‘stole’ close to one million low-mass stars from it.

Globular clusters move in extended elliptical orbits that periodically take them through the densely populated regions of our galaxy, and then high above and below the plane (the ‘halo’).

When venturing too close to the innermost dense regions of our galaxy, (the ‘bulge’), a globular cluster can be perturbed and its smallest stars ripped away.

The astronomers, led by Guido De Marchi of the European Space Agency, measured the brightness and colours of more than 16 000 stars within the Messier 12 cluster with one of the Unit Telescopes of ESO’s VLT at Cerro Paranal in Chile. The team could study stars that are 50 million times fainter than those seen with the unaided eye.

Messier 12

Central part of Messier 12 as seen by the ESO telescope “In the solar neighbourhood and in most stellar clusters, the least massive stars are by far the most common. But our observations with the VLT show this is not the case for Messier 12,” said De [...]

Happy New Year from Jupiter!

happy-new-year-from-jupiter

Copyright ESA

As the year draws to a close international teams of scientists have been enjoying a unique opportunity to make co-ordinated observations of the largest planet in our Solar System. The NASA/ESA/ASI Cassini-Huygens spacecraft made its closest approach to Jupiter, around 9.7 million kilometres, yesterday morning.

NASA’s Galileo spacecraft has already been orbiting Jupiter since 1995. Scientists using instruments on both Cassini-Huygens and Galileo gave a preview at a press conference at JPL of what they are beginning to discover from their joint studies.

Large storms on Jupiter, which can be larger than those on Earth and last for centuries, gain energy from swallowing smaller storms, preliminary analysis of Jupiter movies taken by Cassini-Huygens suggest. The smaller storms pull their energy from lower depths, according to information collected by Galileo.

The joint observations continue for another three months, but Cassini-Huygens is already speeding onwards towards the final destination of its seven-year interplanetary cruise, Saturn. This final planetary swing-by was vital to allow it to acquire the velocity needed to reach Saturn.

Even at such a vast distance the gravity of Jupiter is sufficient to bend Cassini-Huygens’ trajectory and re-direct it to Saturn. During the flyby ESA’s Huygens probe is [...]

Unveiling the nature of a dusty galaxy

unveiling-the-nature-of-a-dusty-galaxy-j1-j2

The ESA/NASA Hubble Space Telescope has made the first detailed optical observations of an example of a remarkable class of galaxies by using the additional magnifying power of a huge galaxy cluster to extend its range. The galaxy, named J1/J2, belongs to a remote population of galaxies. Although extremely luminous, the galaxies are obscured by enormous quantities of dust – the smoky residue of the life cycle of massive stars – and have so far only been seen by sub-millimetre telescopes. buy com domain . The Hubble observation has enabled astronomers to investigate the connection between this distant population of ‘hidden’ dust-enshrouded, intensely star-forming galaxies and the less dusty galaxies that are readily observed with optical telescopes.

Clusters of galaxies can act as a gravitational lens, magnifying and distorting the galaxies behind them and so are also known as ‘natural telescopes’. The well-known ‘gravitational arcs’ are a result of gravitational lensing by large clusters. Galaxy clusters can amplify the light from background objects by up to 100 times, but generally the magnification power is an order of magnitude less – comparable to that of a pair of binoculars.

A group of European and American astronomers led by Jean-Paul Kneib [...]